Size (Diameter) of the FUE Punch Tool
The diameter (size) of the FUE punch tool varies from around 0.6 mm all the way up to 1.2 mm with 0.75 to 0.9 mm being fairly standard. Because the size of the follicular units differ, most hair restoration physicians now use a variety of different sized punches during an FUE procedure. For example, a 0.75 mm FUE punch may be used to remove a small, 1 hair follicular unit because it will decrease transection and prevent unnecessary scarring. However, a 0.75 mm punch would be too narrow for a 3-4 hair graft, and would cause transection during removal. For a graft of this size, a 0.9 mm punch would likely be more appropriate.
In general, smaller punches are ideal for reducing the circular scarring associated with FUE procedures, but are not effective for removing larger grafts. Conversely, larger punches are best suited for removing bigger follicular units, but also create a greater amount of scarring. Normally, physicians strike an appropriate balance between scarring and transection rate by using a variety of different diameter punch tools for different sized follicular units.
Also, learn more about "Automated and Robotic Assisted FUE Extraction Devices.